System for filling closed containers with volatile liquids



Oct. 8, 1963 P. R. GREEN ETAL 3,105,071

SYSTEM FOR FILLING CLOSED CONTAINERS WITH VOLATILE LIQUIDS Filed Aug.16, 1961 STORAGE TANK SPLASH TANK aul R. Green Franklin G. PulcunisPatent Attorney United States Patent 3,106,071 SYSTEM FOR FILLING CLOSEDCONTAINERS WITH VOLATILE LIQUTDS Paul R. Green, Cranford, and FranklinG. Palcanis, Mountainside, Nd, assignors to Esso Research andEngineering ompany, a corporation of Delaware Filed Aug. 16, 196i, Ser.No. 131,893 8 Claims. (Cl. 6255) This invention relates to a systemwherein volatile liquids such as liquid propane or liquid butane may betransferred from one container to another container. It relatesparticularly to a system of the kind described employing a closedstorage container and a closed receiving container; that is, a systemwherein the materials being transferred are maintained in the liquidstate at substantially atmospheric temperature by the application ofpressure.

When a volatile liquid is admitted into a closed container, the spacewithin the container for vapor originally present therein and vaporresulting from evaporation of the admitted volatile liquid inside thecontainer will decrease progressively as the quantity of liquid withinthe container increases; consequently, the vapor will be compressed,resulting in a temperature rise in the vapor. A part of this vapor iscondensed upon coming into contact with the surface of the liquidwithin-the container, and as the heat of condensation resultingtherefrom cannot be distributed extremely rapidly throughout the entireliquid mass by natural heat flow the temperature prevailing at theliquid surface is higher than the temperature of the liquid below thesurface. This compression of vapor and the resulting non-uniformtemperature distribution in the liquid tend to cause the pressure of thevapor within the container to exceed the vapor pressure of the liquidcorresponding to the mean liquid temperature.

Various techniques have been proposed to reduce if not eliminate theafore-described pressure rise in the vapor space of a closed containerbeing filled with a volatile liquid, that is, techniques other than thatof simply permitting the vapor to escape to the atmosphere through asuitably adjusted relief or safety valve. Such escape is usuallyundesirable not only because the vapors involved are often hazardous dueto their flammability as in the cases of propane and butane, but alsobecause of the attendant loss of valuable materials.

One transfer and/ or filling technique known to the prior art comprisesthe step of spray loading of volatile liquid directly into a receivingcontainer from the top thereof, so as to obtain contact and heattransfer between the liquid being introduced and the vapor alreadypresent in the container. This results in some degree of cooling of thelatter owing to the falling of the introduced liquid through the vaporand onto the liquid surface. There is then also a slight improvement inthe distribution of the heat of condensation to the lower, colder layersof the liquid within the container because of greater turbulence. It hasbeen found in practice, however, that this technique does not achieve asufficient cooling of the vapor to substantially prevent a rise ofpressure within the container, especially in the course of an extendedfilling operation.

Another technique makes use of a gas compression system wherein thevapors generated during transfer are withdrawn from the receivingcontainer, compressed, cooled, and condensed, and the condensatereturned to the receiving container. This technique, while effective, isobviously one which requires at least some additional and expensiveequipment.

Still another technique makes use of a vapor balance system wherein avapor line is employed to equalize pres- 3,106,071 Patented Oct. 8, 1963ice sures between the receiving container and the storage container'wherefrom the receiving container is filled. This technique, althoughsimple, may be costly due to the length of vapor line required in someinstallations.

Even still another technique makes use of a condensing system wherein aheat exchanger and a condensate collector are employed. This technique,like that making use of a gas compression system, requires at least someadditional and expensive equipment.

An object of the present invention is to improve upon existingtechniques for transferring volatile liquids from one closed containerto another by simplifying the equipment needed to effect such transferefiiciently, reducing the cost of this equipment, or achieving both asimplification and a cost reduction.

According to the present invention, a container filling or volatileliquid transfer system is provided which includes a relatively smalldrum, tank, or container known generally as a splash tank. Volatileliquid intended for ultimate loading into a receiving container istransferred to this tank from a storage container or other source,entering the splash tank at the top to flow downwardly as a spraythrough the vapor space thereof rather than entering at or near thebottom to have to mix initiaily with any liquid already in the tank.This form of entry furnishes at least some cooling and condensation ofvapors in the spash tank.

A liquid line leads away from the bottom of the splash tank, and bymeans of suitable fittings may be placed in filling connection with areceiving container. Also leading away from the splash tank is a linewhere-through vapors may be returned from a receiving container. It iscontemplated that the storage container and the splash tank will beseparated by a considerable distance while the splash tank itself willbe so located that a receiving container may be brought up quite closeto it. Receiving containers are contemplated to be in a variety of formssuch as tanks of substantial size mounted upon highway vehicles, railwaycars, marine barges, and even aircraft, as well as being the customarysmall pressure cylinders.

One advantage of this invention in its apparatus embodiment is that itcan be fabricated of readily available materials. Another advantage isthat it can be fabricated relatively inexpensively in the field foreconomical operation. Still another advantage is that it does notrequire long vapor balance lines. Even still another advantage is thatit does not require compression or heat exchange equipment, or anyparticular supply of cooling Water.

These and other advantages of the present invention as well as itsnature and substance will be more clearly perceived and fully understoodby referring to the following description and claims taken in connectionwith the accompanying drawing in which:

FIG. 1 represents a partially pictorial, partially schematic view of acontainer filling system according to this invention in which the splashtank is disposed substantially vertically, and liquid is delivered fromthis tank to a receiving container by means of a pump;

FIG. 2 represents a vertical splash tank and connections made theretofor use in a system according to this invention in which liquid isdelivered from this tank to a receiving container by means of gravity,and

FIG. 3 represents a horizontally disposed splash tank and connectionsmade thereto.

Referring now to the drawing in detail, especially to FIG. 1 thereof, abulk storage tank or container for volatile liquid materials underpressure such as liquefied propane or liquefied butane is designated 10.This container will have suitable fittings for filling and venting.

It may be elevated :on legs or stanchions l2 and 14 as shown, or it maybe seated directly on earth formation. Particular details ofconstruction and installation of storage container it do not, however,constitute any part of the present invention. Leading :out of the bottomof the interior region of storage container is a liquid discharge l-ine16 which extends to and connects with the inlet side of product pump 18which may be of any suitable kind. Liquid discharge line 24 extends fromthe outlet side of pump '13 to and through thetop of splash tank 22, andterminates within the top of the interior region of this tank in sprayhead or spray nozzle 24.

Splash tank 22 which is considerably smaller than storage container 10may be elevated on legs or stan chions 26 and 28 as shown, or it may beseated directly on earth formation. It is provided with a safety orrelief valve 30, and with a liquid level sensing and signal generatingdevice 32 which may be of any suitable kind. Within the splash tankthere is a body of liquid 34 in the process of transfer having a surface36, the level of which is intended to be maintained betweenpredetermined upper and lower limits according to the setting of sensingdevice 32. Above liquid surface 36 is vapor region 38 down through whichpasses liquid from storage tank 10 issuing out of spray head 24.

Leading out of the bottom of the interior region of splash tank 22 is aliquid discharge line 40 which extends to and connects with the inletside of booster transfer pump 42 which may be of any suitable kind.Liquid discharge 'line i iextends from the outlet side of pump 42 to theinlet side of articulated pipe structure 4a which is appropriatelysupported and actuated for raising and lowering by means not shown. Nearits outlet side, this structure contains a stop valve 48, and at itsoutlet side it is connected through flanged joint 50' with the inlet orliquid filling fitting of receiving container 52 which is shown as theliquid-holding element of a railway tank car. This filling fittingincludes a stop valve 54 closely below flanged joint 50, and it extendsinto the lower region of receiving container 52. The receiving containeritself is considerably smaller than storage container 10, but it may belarger than splash tank 22.

Discharge line 44 contains a power-operated throttle valve 56 whichreceives actuating signals from sensing device 32 through connection 58.This connection may be of an electrical nature as indicated, but it mayalso be a pneumatic, hydraulic, mechanical linkage, or any otherappropriate connection depending upon the choice of liquid level sensingand signal generating device, and the power means selected for operatingvalve 56.

When the level of liquid surface 36 approaches its pre determined lowerlimit, sensing device 32 generates a signal causing valve 56 to becomemore nearly closed, and thus restrict the delivery from pump 42 to allowthe liquid level in tank 22 to rise. correspondingly, when the level ofliquid surface 36 approaches its predetermined upper limit, sensingdevice 32 generates a signal causing valve 56 to become wider open, andthus permit greater delivery from pump 42 to cause the liquid level inthe splash tank to fall. The liquid level sensing and signal generatingdevice may, of course, be designed and installed cooperatively withthrottle valve 56 to control or maintain liquid surface 36 at or veryclosely around a single predetermined level in splash tank 22. Thiswould be in place of exercising liquid level control across a range oflevels between predetermined upper and lower limits as describedhereinbefore.

Receiving container 52 is provided with a vapor outlet fitting for useduring filling operations. This fitting extends outwardly from the upperregion of this container, and includes a stop valve 60. A secondarticulated pipe structure 62, appropriately supported and actuated forraising and lowering by means not shown, makes connection at its inletside through flanged joint 54 with the vapor outlet fitting of container52. Near its inlet side pipe structure 62 contains a stop valve 65, andfrom its outlet side a vapor return or vapor balance line 68 extends, asillustrated, to the top of splash tank 22, and makes connectiontherethrough to the interior of this tank in its vapor region 35. it isalso within the contemplation of this invention that vapor return line63 make connection to the interior of the splash tank below thepredetermined lower limit of the level of liquid surface 36.

In the operation of the container filling system of FIG. 1, flangedjoints 50 and 64 having been made up tight and stop valves 43, 54, 6tand 66 having been opened, pump 18 withdraws volatile liquid materialunder pressure from storage container l0, and discharges it into splashtank 22 through spray head 24. The liquid streams descending from thespray head have at least a tendency to cool and condense vaporousmaterial in upper region 33 of the splash tank, and of course they actto replenish liquid body 34 in the tank as pump 42 withdraws liquidtherefrom. Maintenance of the level of liquid surface 36 within splashtank 22 is effected by cooperative action of sensing device 32 andthrottle valve 56 as already described.

Liquid material discharged by pump 42 through line 44 and pipe structure46 flows into receiving container 52 near the bottom thereof through itsfilling fitting. Any vapor initially in the receiving container and alsoany vapor in this container evolved from liquid filling thereinto mayflow back to vapor region 38 of the splash tank through pipe structure62 and line as upon the pressure in the vapor region of the receivingcontainer tending to become at all elevated above that in the vaporregion of the splash tank. Vapor entering the splash tank from thereceiving container through the connections shown will be spray andsplash cooled and at least reduced in pressure if not fully condensed byliquid flowing into tank 22 through spray head 24. Vapor bubbled intothe splash tank from the receiving container by an alternate con nectionbelow liquid surface 36 will likewise be cooled and at least partlycondensed. At any rate, with some open path for flow of vapor back fromthe receiving container to the splash tank, there will be an orderlyfilling of the receiving container without either an undesirable loss ofvaluable vaporized formerly liquid material from the system, or an unduerise of pressure in the receiving container.

When the filling operation is completed as indicated by appropriategaging means associated with receiving container 52, pumps 18 and 42 maybe shut down,- and stop valves 48, 54, 6t), and 66 closed to isolate thefilling system from the receiving container, and maintain both tig'against the escape of either liquid or vaporous material. With the fourstop valves closed, flanged joints 5% and 64 may be broken; the filledreceiving container rolled away from filling location; an emptyreceiving container brought into this location; flanged joints 5t and 64made up to it; the four stop valves opened, and pumps 18 and 42 startedto commence another filling operation.

Referring next to FIG. 2, it is contemplated that the splash tank of acontainer filling system according to this invention may be mountedsufliciently high with respect to the loading location of receivingcontainers that liquid material can be delivered from it into areceiving container simply by gravity. In an example of such anarrangement, splash tank 122 is elevated on cross-braced legs orstanchions 126 and 128. Liquid material is de livered to the splash tankthrough line 12% from a storage container and by a product pump notshown, actually entering the tank in its upper or vapor region through aspray head or spray nozzle 124.

Splash tank 122 is provided with a relief or safety valve I39, and witha liquid level sensing and signal generating device 132. Within thesplash tank there is a body of liquid 134 in the process of transferhaving a surface 136, the level of which is intended to he maintainedbetween predetermined upper and lower limits according to the setting ofsensing device 132. Above liquid surface 136 is vapor region 138, downthrough which passes liquid issuing out of spray head 124. Leading outof the bottom of splash tank 122 is a liquid discharge line 145 whichinclines downwardly toward a receiving container, not shown, at a levellower than the splash tank. Leading into the top of splash tank 122 is avapor return or vapor balance line 168 inclining upwardly from thereceiving container.

Liquid line 120 contains a power-operated throttle valve which receivesactuating signals from sensing device 132 through connection 158. Whenthe level of liquid surface 136 approaches its predetermined upperlimit, sensing device 132 generates a signal causing valve 156 to becomemore nearly closed, and thus restrict delivery from the product pump toallow the liquid level in tank 122 to fall. correspondingly, when thelevel of liquid surface 136 approaches its predetermined lower limit,sensing device 132 generates a signal causing valve 156 to become wideropen, and thus permit greater delivery from the product pump to causethe liquid level in the splash tank to rise.

Referring finally to'FIG. 3, it is contemplated that the splash tank ofa container filling system according to this invention may be mountedsubstantially horizontally. In an example of such an arrangement,horizontal tank 222 is elevated on legs or stanchions 226 and 228.Liquid material is delivered to the splash tank through line 220 from astorage container and by a product pump not shown, actually entering thetank through a plurality of spray heads or spray nozzles 224 in theupper or vapor region 238 of the tank above surface 236 of liquid body234. Splash tank 222 is provided with a relief or safety valve 230, andwith a liquid level sensing and signal generating device 232. Leadingout of the bottom of the splash tank is a liquid discharge line 240, andleading into the top of the tank is a vapor return or vapor balance line268.

It is possible to use splash tank 222 in either the system of tank 22 orthat of tank 122. Said in other words, liquid line 240 may either go tothe inlet side of a booster transfer pump such as 42 with sensing device232 providing signals through connection 258 to a throttle valve such as56 on the outlet side of this pump, or else go directly to a receivingcontainer at a loading location lower than splash tank 222 with sensingdevice 232 being connected to :a throttle valve such as 156 in liquidline 229 on the outlet side of the product pump. Within tank 222 itself,the plural number of sprays and the splashing oil of the extendedsurface 236 of the liquid body makes up for the shortness of the spraysto give goodcontacting of vapor with liquid and consequent reasonabledegree of cooling of vapor in upper region 238 of the splash tank.

It is intended to secure protection by Letters Patent of theforegoing-described invention in all its aspects to the broadest extentthat the prior art allows.

What is claimed is:

1. A system for filling closed containers with volatile liquids, saidsystem comprising (:1) a closed storage container for liquefied productmaterials under pressure such as liquefied propane or liquefied butane,said storage container having a bottom interior region, (2) a productpump having an inlet side and an outlet side, (3) a liquid dischargeline extending from the bottom interior region of said storage containerto the inlet side of said product pump, (4) a closed splash tank havingan interior region including a top and a bottom, (5) a liquid dischargeline extending from the outlet side of said product pump to the topinterior region of said splash tank, (6) a liquid discharge lineextending from the bottom interior region of said splash tank, said linehaving an outlet end removed from said splash tank which is adapted tobe connected to a closed receiving container, and said line includingvalve means closely adjacent its outlet end whereby the flow of liquidthrough said line may be stopped, and (7) a vapor return line extendingto the interior region of said splash tank, said line having an inletend removed from said splash tank Which is adapted to be connected to aclosed receiving container, and said line including valve means closelyadjacent its inlet end whereby the fiow of vapor through said line maybe stopped.

2. A system according to claim -1 in which said splash tank is disposedsubstantially vertically.

3. A system according to claim 1 in which said splash tank is disposedsubstantially horizontally.

4. A system according to claim 1 in which said liquid discharge lineextending from the outlet side of said product pump to the top interiorregion of said splash tank terminates within this region in at least onespray head.

5. A system according to claim 1 in which said vapor return lineextending to the interior region of said splash tank terminates Withinthe top interior region thereof.

6. A system according to claim 1 in which said liquid discharge lineextending from the bottom interior region of said storage container tothe inlet side of said product pump and said liquid discharge lineextending from the outlet side of said product pump to the top interiorregion of said splash tank taken together are substantially longer thansaid liquid discharge line extending from the bottom interior region ofsaid splash tank.

7. A system for filling closed containers with volatile liquids, saidsystem comprising (1) a closed storage container for liquefied productmaterials under pressure such as liquefied propane or liquefied butane,said storage container having a bottom interior region, (2) a productpump having an inlet side and an outlet side, (3) a liquid dischargeline extending from the bottom interior region of said storage containerto the inlet side of said product pump, (4) a closed splash tank havingan interior region including a top and a bottom, (5) liquid levelsensing and signal generating means operatively associated with saidsplash tank in its interior region, (6) a liquid discharge lineextending from the outlet side of said product pump to the top interiorregion of said splash tank, (7 a booster transfer pump having an inletside and an outlet side, (8) a liquid discharge line extending from thebottom interior region of said splash tank to the inlet side of saidbooster transfer pump, (9) a liquid discharge line extending from theoutlet side of said booster transfer pump, said line having an outletend removed from said booster transfer pump which is adapted to beconnected to a closed receiving container, and said line including valvemeans closely adjacent its outlet end whereby the flow of liquid throughsaid line may be stopped, (10) a power-operated throttle valve in saidliquid discharge line extending vfrom the outlet side of said boostertransfer pump, said throttle valve being located in said line betweenthe outlet side of said booster transfer pump and said afore-mentionedvalve means, (11) a connection between said liquid level sensing andsignal generating means and said throttle valve wherethrough actuatingsignals are received by said throttle valve from said liquid levelsensing and signal generating means, said throttle valve and said liquidlevel sensing and signal generating means being so connected that arising level of liquid within said splash tank causes said throttlevalve to become Wider open and a falling level of liquid Within saidsplash tank causes said throttle valve to become more nearly closed, and(12) a vapor return line extending to the interior region of said splashtank, said line having an inlet end removed from said splash tank whichis adapted to be connected to said closed receiving container, and saidline including valve means closely adjacent its inlet end whereby theflow of vapor through said line may be stopped.

8. A system for filling closed containers with volatile liquids, saidsystem comprising (1) a closed storage container for liquefied productmaterials under pressure such as liquefied propane or liquefied butane,said storage con- 7 tainer having a bottom interior region, (2) aproduct pump having an inlet side and an outlet side. (3) a liquiddischarge line extending from the bottom interior region of said storagecontainer to the inlet side of said product pump, (4) a closed splashtank having an interior region including a top and a bottom, (5) liquidlevel sensing and signal generating means operatively associated withsaid splash tank in its interior region, (6) a liquid discharge lineextending from the outlet side of said product pump to the top interiorregion of said splash tank, (7) a power-operated throttle valve in saidliquid discharge line extending from the outlet side of said productpump to the top interior region of said splash tank, (8) a connectionbetween said liquid level sensing and signal generating means and saidthrottle valve therethrough [actuating signals are received by saidthrottle valve from said liquid level sensing and signal generatingmeans, said throttle valve and said liquid level sensing and signalgenerating means being so connected that a rising level of liquid withinsaid splash tank causes said throttle valve to become more nearly closedand a falling level of liquid Within said splash '8 tank causes saidthrottle valve to become wider open, (9) a liquid discharge lineextending from the bottom interior region of said splash tank, said linehaving an outlet end removed from said splash tank and at a lower levelthan the bottom interior region thereof which outlet end is adapted tobe connected to a closed receiving container, and said line includingvalve means closely adjacent its outlet end whereby the flow of liquidthrough said line may be stopped, and (10) a vapor return line extendingto the interior region of said splash tank, said line having an inletend removed from said splash tank and at a lower level than the topinterior region thereof which inlet end is adapted to be connected tosaid closed receiving container, and said line including valve meansclosely adjacent its inlet end whereby the flow of vapor through saidline may be stopped.

References (liter! in the file of this patent UNITED STATES PATENTS2,487,863 Garretson Nov. 15, 1949 2,764,873 Mooyar't Oct. 2, 19562,895,305 Reed July 21, 1959

1. A SYSTEM FOR FILLING CLOSED CONTAINERS WITH VOLATILE LIQUIDS, SAID SYSTEM COMPRISING (1) A CLOSED STORAGE CONTAINER FOR LIQUEFIED PRODUCT MATERIALS UNDER PRESSURE SUCH AS LIQUEFIED PROPANE OR LIQUEFIED BUTANE, SAID STORAGE CONTAINER HAVING A BOTTOM INTERIOR REGION, (2) A PRODUCT PUMP HAVING AN INLET SIDE AND AN OUTLET SIDE, (3) A LIQUID DISCHARGE LINE EXTENDING FROM THE BOTTOM INTERIOR REGION OF SAID STORAGE CONTAINER TO THE INLET SIDE OF SAID PRODUCT PUMP, (4) A CLOSED SPLASH TANK HAVING AN INTERIOR REGION INCLUDING A TOP AND A BOTTOM, (5) A LIQUID DISCHARGE LINE EXTENDING FROM THE OUTLET SIDE OF SAID PRODUCT PUMP TO THE TOP INTERIOR REGION OF SAID SPLASH TANK, (6) A LIQUID DISCHARGE LINE EXTENDING FROM THE BOTTOM INTERIOR REGION OF SAID SPLASH TANK, SAID LINE HAVING AND OUTLET END REMOVED FROM SAID SPLASH TANK WHICH IS ADAPTED TO BE CONNECTED TO A CLOSED RECEIVING CONTAINER, AND SAID LINE INCLUDING VALVE MEANS CLOSELY ADJACENT ITS OUTLET END WHEREBY THE FLOW OF LIQUID THROUGH SAID LINE MAY BE STOPPED, AND (7) A VAPOR RETURN LINE EXTENDNG TO THE INTERIOR REGION OF SAID SPLASH TANK, SAID LINE HAVING AN INLET END REMOVED FROM SAID SPLASH TANK WHICH IS ADAPTED TO BE CONNECTED TO A CLOSED RECEIVING CONTAINER, AND SAID LINE INCLUDING VALVE MEANS CLOSELY ADJACENT ITS INLET END WHEREBY THE FLOW OF VAPOR THROUGH SAID LINE MAY BE STOPPED. 